Pseudotsuga Carričre 1867

Douglas-fir

This tree diagram shows the relationships between several groups of organisms.

The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

You can click on the root to travel down the Tree of Life all the way to the root of all Life, and you can click on the names of descendent subgroups to travel up the Tree of Life all the way to individual species.

Introduction

Pseudotsuga is a small genus of approximately five species distributed in eastern Asia and western North America. Pseudotsuga menziesii, with a distribution from western Canada to central Mexico, is one of the most economically important timber species in the world.

Discussion of Phylogenetic Relationships

Farjon (1990) recognized only four species of Pseudotsuga: Pseudotsuga macrocarpa from southern California, Pseudotsuga menziesii ranging from Canada to south-central Mexico, Pseudotsuga japonica from southern Japan, and Pseudotsuga sinensis from China. Included in the ToL phylogeny is also P. wilsoniana from Taiwan. In addition to P. wilsoniana, several other species have been segregated from Pseudotsuga sinensis (P. forrestii, P. salvadorii, P. gaussenii, P. brevifolia, P. xichangensis), but these have not been widely accepted. Mexican botanists tend to recognize four segregate species of Pseudotsuga menziesii var. glauca in Mexico: P. macrolepis, P. rehderi, P. guinieri, and P. flahaultii (Martínez 1963).

Relationships among the widely-accepted species were studied by Strauss et al. 1990 using DNA restriction fragments and by Gernandt and Liston (1999) using nuclear ribosomal DNA.

Each ToL branch page provides a synopsis of the characteristics of
a group of organisms representing a branch of the Tree of Life. The
major distinction between a branch and a leaf of
the Tree of Life is that each branch can be further subdivided into
descendent branches, that is, subgroups representing distinct genetic
lineages.